U.S. patent application Ser. No. 99,953, entitled "System for High Resolution Exposure Address With Coarser Resolution Exposing Array", filed Sept. 23, 1987, by Agostinelli and Mir, describes advantageous imaging devices wherein an object source array (e.g. comprising a linear array of light valve elements) of relatively coarse resolution is imaged at a print zone in a manner providing a relatively higher resolution exposure. In one preferred embodiment, this approach utilizes (i) an object array having exposing pixels of width (W) located with intervening non-exposing spaces so as to have a center-to-center spacing S and (ii) a scan multiplexing optical system, e.g. including lens means and a mirror, which indexes the image of the exposing array in a number of increments, approximately S.div.W, to successive positions across a linear print zone. This system offers important advantages in simplifying array fabrication and in reducing electronic complexities.
In certain applications, e.g. in printing high quality continuous tone images, undesirable banding artifacts have been found to occur in the print output from the above-described system. We have discovered the cause of these artifacts to be the emphasis which that multiplex system adds to the non-uniform intensity profile of source light transmitted to the light valve array.